[PATCH v2] PR tree-optimization/126242: Check range is defined to avoid ICE.

"Roger Sayle" <[email protected]> Mon, 3 Aug 2026 18:40:40 +0100
Newsgroups gmane.comp.gcc.patches
Message-ID <[email protected]>
Hi Richard,
Here's the latest revision of my patch to resolve PR 126242 (and 126325),
incorporating Richard Biener's feedback to simplify the logic, eliminating
itype_ok and always using calling gimple_match_range_of_expr.  This
version also resolves PR tree-optimization/126325 introduced/exposed
by the same change, checking that when transforming (float)x < C into
x < (int)C that (int)C is exactly representable, i.e. that (float)(int)C ==
C.

This patch has been tested on x86_64-pc-linux-gnu with make bootstrap
and make -k check, both with and without --target_board=unix{-m32}
with no new failures.  Ok for mainline?


2026-08-03  Roger Sayle  <[email protected]>
            Richard Biener  <[email protected]>

gcc/ChangeLog
        PR tree-optimization/126242
        PR tree-optimization/126325
        * match.pd ((FTYPE) N CMP CST): Always attempt to initialize
        value range information.  Check undefined_p before using range
        bounds.  Check that icst_val hasn't overflowed, i.e. that
        (FTYPE)ICST == CST, before transforming to integer comparison.

gcc/testsuite/ChangeLog
        PR tree-optimization/126242
        PR tree-optimization/126325
        * gcc.dg/pr126325.c: New test case.
        * gfortran.dg/pr126242.f90: New reduced test case.
        * gfortran.dg/pr41928-2.f90: Also compile pr41928.f90 with -Ofast.

Thanks again.
Roger
--
patchvr2.txt (text/plain, 14.3 KB)
diff --git a/gcc/match.pd b/gcc/match.pd
index 89ed2aaaa52..75d952a0e04 100644
--- a/gcc/match.pd
+++ b/gcc/match.pd
@@ -7800,10 +7800,8 @@ DEFINE_INT_AND_FLOAT_ROUND_FN (RINT)
     (with
      {
        tree itype = TREE_TYPE (@0);
-       signop isign = TYPE_SIGN (itype);
        format_helper fmt (REAL_MODE_FORMAT (TYPE_MODE (TREE_TYPE (@1))));
-       bool itype_ok = fmt.can_represent_integral_type_p (itype);
-       bool value_ok = itype_ok;
+       bool value_ok = fmt.can_represent_integral_type_p (itype);
        const REAL_VALUE_TYPE *cst = TREE_REAL_CST_PTR (@1);
        /* Be careful to preserve any potential exceptions due to NaNs.
 	  qNaNs are ok in == or != context.  */
@@ -7814,8 +7812,7 @@ DEFINE_INT_AND_FLOAT_ROUND_FN (RINT)
 				  && HONOR_SNANS (TREE_TYPE (@1))));
 #if GIMPLE
        int_range_max vr;
-       if (!value_ok
-	   && gimple_match_range_of_expr (vr, @0, @2))
+       if (gimple_match_range_of_expr (vr, @0, @2))
 	 value_ok = fmt.can_represent_range_value_p (&vr);
 #endif
        /* Conversion may raise FPE_INEXACT with -ftrapping-math.  */
@@ -7830,7 +7827,7 @@ DEFINE_INT_AND_FLOAT_ROUND_FN (RINT)
 	 wide_int imin_val = wi::min_value (itype);
 	 wide_int imax_val = wi::max_value (itype);
 #if GIMPLE
-	 if (!itype_ok)
+	 if (!vr.undefined_p ())
 	   {
 	     imin_val = vr.lower_bound ();
 	     imax_val = vr.upper_bound ();
@@ -7853,6 +7850,14 @@ DEFINE_INT_AND_FLOAT_ROUND_FN (RINT)
 	 bool overflow_p = false;
 	 wide_int icst_val
 	   = real_to_integer (&icst, &overflow_p, TYPE_PRECISION (itype));
+	 /* Double check that icst is representable in itype.  */
+	 if (isign == SIGNED && !overflow_p)
+	   {
+	     REAL_VALUE_TYPE check;
+	     real_from_integer (&check, fmt, icst_val, isign);
+	     if (!real_identical (&check, &icst))
+	       overflow_p = true;
+	   }
        }
        (switch
 	/* Optimize cases when CST is outside of ITYPE's range.  */
@@ -7871,12 +7876,14 @@ DEFINE_INT_AND_FLOAT_ROUND_FN (RINT)
 	/* Remove cast if CST is an integer representable by ITYPE,
 	   and it is safe to do so.  */
 	(if (cst_int_p
+	     && !overflow_p
 	     && fold_cmp_float_cst_p (imin_val, imax_val, cmp, &icst, fmt,
 				      icst_val, isign))
 	 (cmp @0 { wide_int_to_tree (itype, icst_val); })
 	)
 	/* Otherwise replace with sensible integer constant.  */
 	(if (!cst_int_p
+	     && !overflow_p
 	     && fold_cmp_float_cst_p (imin_val, imax_val, icmp, &icst, fmt,
 				      icst_val, isign))
 	 (icmp @0 { wide_int_to_tree (itype, icst_val); })))))))))
diff --git a/gcc/testsuite/gfortran.dg/pr126242.f90 b/gcc/testsuite/gfortran.dg/pr126242.f90
new file mode 100644
index 00000000000..293c9bfe2fc
--- /dev/null
+++ b/gcc/testsuite/gfortran.dg/pr126242.f90
@@ -0,0 +1,5 @@
+! { dg-do compile }
+! { dg-options "-Ofast -w" }
+DO bx=2,lb
+END DO
+END
diff --git a/gcc/testsuite/gfortran.dg/pr41928-2.f90 b/gcc/testsuite/gfortran.dg/pr41928-2.f90
new file mode 100644
index 00000000000..d96857afd8d
--- /dev/null
+++ b/gcc/testsuite/gfortran.dg/pr41928-2.f90
@@ -0,0 +1,263 @@
+! { dg-do compile }
+! { dg-options "-Ofast -w" }
+MODULE kinds
+  INTEGER, PARAMETER :: dp = SELECTED_REAL_KIND ( 14, 200 )
+  INTEGER, DIMENSION(:), ALLOCATABLE     :: nco,ncoset,nso,nsoset
+  INTEGER, DIMENSION(:,:,:), ALLOCATABLE :: co,coset
+END MODULE kinds
+MODULE ai_moments
+  USE kinds
+CONTAINS
+  SUBROUTINE cossin(la_max,npgfa,zeta,rpgfa,la_min,&
+                    lb_max,npgfb,zetb,rpgfb,lb_min,&
+                    rac,rbc,kvec,cosab,sinab)
+    REAL(KIND=dp), DIMENSION(ncoset(la_max),&
+      ncoset(lb_max))                        :: sc, ss
+    DO ipgf=1,npgfa
+      DO jpgf=1,npgfb
+        IF (la_max > 0) THEN
+          DO la=2,la_max
+            DO ax=2,la
+              DO ay=0,la-ax
+                sc(coset(ax,ay,az),1) = rap(1)*sc(coset(ax-1,ay,az),1) +&
+                              f2 *          kvec(1)*ss(coset(ax-1,ay,az),1)
+                ss(coset(ax,ay,az),1) = rap(1)*ss(coset(ax-1,ay,az),1) +&
+                              f2 *          kvec(1)*sc(coset(ax-1,ay,az),1)
+              END DO
+            END DO
+          END DO
+          IF (lb_max > 0) THEN
+            DO lb=2,lb_max
+              ss(1,coset(0,0,lb)) = rbp(3)*ss(1,coset(0,0,lb-1)) +&
+                           f2 *         kvec(3)*sc(1,coset(0,0,lb-1))
+              DO bx=2,lb
+                DO by=0,lb-bx
+                  ss(1,coset(bx,by,bz)) = rbp(1)*ss(1,coset(bx-1,by,bz)) +&
+                               f2 *           kvec(1)*sc(1,coset(bx-1,by,bz))
+                END DO
+              END DO
+            END DO
+          END IF
+        END IF
+       DO j=ncoset(lb_min-1)+1,ncoset(lb_max)
+        END DO
+      END DO
+    END DO
+  END SUBROUTINE cossin
+  SUBROUTINE moment(la_max,npgfa,zeta,rpgfa,la_min,&
+                    lb_max,npgfb,zetb,rpgfb,&
+                    lc_max,rac,rbc,mab)
+    REAL(KIND=dp), DIMENSION(:), INTENT(IN)  :: zeta, rpgfa
+    REAL(KIND=dp), DIMENSION(:), INTENT(IN)  :: zetb, rpgfb
+    REAL(KIND=dp), DIMENSION(:, :, :), &
+      INTENT(INOUT)                          :: mab
+    REAL(KIND=dp), DIMENSION(3)              :: rab, rap, rbp, rpc
+    REAL(KIND=dp), DIMENSION(ncoset(la_max),&
+      ncoset(lb_max), ncoset(lc_max))        :: s
+    DO ipgf=1,npgfa
+      DO jpgf=1,npgfb
+        IF (rpgfa(ipgf) + rpgfb(jpgf) < dab) THEN
+          DO k=1, ncoset(lc_max)-1
+            DO j=nb+1,nb+ncoset(lb_max)
+              DO i=na+1,na+ncoset(la_max)
+                mab(i,j,k) = 0.0_dp
+              END DO
+            END DO
+          END DO
+        END IF
+        rpc = zetp*(zeta(ipgf)*rac+zetb(jpgf)*rbc)
+        DO l=2, ncoset(lc_max)
+          lx = indco(1,l)
+          l2 = 0
+          IF ( lz > 0 ) THEN
+            IF ( lz > 1 ) l2 = coset(lx,ly,lz-2)
+          ELSE IF ( ly > 0 ) THEN
+            IF ( ly > 1 ) l2 = coset(lx,ly-2,lz)
+            IF ( lx > 1 ) l2 = coset(lx-2,ly,lz)
+          END IF
+          s(1,1,l) = rpc(i)*s(1,1,l1)
+          IF ( l2 > 0 ) s(1,1,l) = s(1,1,l) + f2*REAL(ni,dp)*s(1,1,l2)
+        END DO
+        DO l = 1, ncoset(lc_max)
+          IF ( lx > 0 ) THEN 
+            lx1 = coset(lx-1,ly,lz)
+          END IF
+          IF ( ly > 0 ) THEN 
+            ly1 = coset(lx,ly-1,lz)
+          END IF
+          IF (la_max > 0) THEN
+            DO la=2,la_max
+              IF ( lz1 > 0 ) s(coset(0,0,la),1,l) = s(coset(0,0,la),1,l) + &
+                             f2z*s(coset(0,0,la-1),1,lz1)
+              IF ( ly1 > 0 ) s(coset(0,1,az),1,l) = s(coset(0,1,az),1,l) + &
+                             f2y*s(coset(0,0,az),1,ly1)
+              DO ay=2,la
+                s(coset(0,ay,az),1,l) = rap(2)*s(coset(0,ay-1,az),1,l) +&
+                                       f2*REAL(ay-1,dp)*s(coset(0,ay-2,az),1,l)
+                IF ( ly1 > 0 ) s(coset(0,ay,az),1,l) = s(coset(0,ay,az),1,l) + &
+                             f2y*s(coset(0,ay-1,az),1,ly1)
+              END DO
+              DO ay=0,la-1
+                IF ( lx1 > 0 ) s(coset(1,ay,az),1,l) = s(coset(1,ay,az),1,l) + &
+                             f2x*s(coset(0,ay,az),1,lx1)
+              END DO
+              DO ax=2,la
+                DO ay=0,la-ax
+                  s(coset(ax,ay,az),1,l) = rap(1)*s(coset(ax-1,ay,az),1,l) +&
+                                          f3*s(coset(ax-2,ay,az),1,l) 
+                  IF ( lx1 > 0 ) s(coset(ax,ay,az),1,l) = s(coset(ax,ay,az),1,l) + &
+                                 f2x*s(coset(ax-1,ay,az),1,lx1)
+                END DO
+              END DO
+            END DO
+            IF (lb_max > 0) THEN
+              DO j=2,ncoset(lb_max)
+                DO i=1,ncoset(la_max)
+                  s(i,j,l) = 0.0_dp
+                END DO
+              END DO
+              DO la=la_start,la_max-1
+                DO ax=0,la
+                  DO ay=0,la-ax
+                    s(coset(ax,ay,az),2,l) = s(coset(ax+1,ay,az),1,l) -&
+                                           rab(1)*s(coset(ax,ay,az),1,l)
+                    s(coset(ax,ay,az),4,l) = s(coset(ax,ay,az+1),1,l) -&
+                                           rab(3)*s(coset(ax,ay,az),1,l)
+                  END DO
+                END DO
+              END DO
+              DO ax=0,la_max
+                DO ay=0,la_max-ax
+                  IF (ax == 0) THEN
+                    s(coset(ax,ay,az),2,l) = rbp(1)*s(coset(ax,ay,az),1,l)
+                  ELSE
+                    s(coset(ax,ay,az),2,l) = rbp(1)*s(coset(ax,ay,az),1,l) +&
+                                            fx*s(coset(ax-1,ay,az),1,l)
+                  END IF
+                  IF (lx1 > 0) s(coset(ax,ay,az),2,l) = s(coset(ax,ay,az),2,l) +&
+                        f2x*s(coset(ax,ay,az),1,lx1)
+                  IF (ay == 0) THEN
+                    s(coset(ax,ay,az),3,l) = rbp(2)*s(coset(ax,ay,az),1,l)
+                  ELSE
+                    s(coset(ax,ay,az),3,l) = rbp(2)*s(coset(ax,ay,az),1,l) +&
+                                            fy*s(coset(ax,ay-1,az),1,l)
+                  END IF
+                  IF (ly1 > 0) s(coset(ax,ay,az),3,l) = s(coset(ax,ay,az),3,l) +&
+                        f2y*s(coset(ax,ay,az),1,ly1)
+                  IF (az == 0) THEN
+                    s(coset(ax,ay,az),4,l) = rbp(3)*s(coset(ax,ay,az),1,l)
+                  ELSE
+                    s(coset(ax,ay,az),4,l) = rbp(3)*s(coset(ax,ay,az),1,l) +&
+                                            fz*s(coset(ax,ay,az-1),1,l)
+                  END IF
+                  IF (lz1 > 0) s(coset(ax,ay,az),4,l) = s(coset(ax,ay,az),4,l) +&
+                        f2z*s(coset(ax,ay,az),1,lz1)
+                END DO
+              END DO
+              DO lb=2,lb_max
+                DO la=la_start,la_max-1
+                  DO ax=0,la
+                    DO ay=0,la-ax
+                      s(coset(ax,ay,az),coset(0,0,lb),l) =&
+                        rab(3)*s(coset(ax,ay,az),coset(0,0,lb-1),l)
+                      DO bx=1,lb
+                        DO by=0,lb-bx
+                          s(coset(ax,ay,az),coset(bx,by,bz),l) =&
+                            rab(1)*s(coset(ax,ay,az),coset(bx-1,by,bz),l)
+                        END DO
+                      END DO
+                    END DO
+                  END DO
+                END DO
+                DO ax=0,la_max
+                  DO ay=0,la_max-ax
+                    IF (az == 0) THEN
+                      s(coset(ax,ay,az),coset(0,0,lb),l) =&
+                        rbp(3)*s(coset(ax,ay,az),coset(0,0,lb-1),l) +&
+                        f3*s(coset(ax,ay,az),coset(0,0,lb-2),l)
+                    END IF
+                    IF (lz1 > 0) s(coset(ax,ay,az),coset(0,0,lb),l) =&
+                                 f2z*s(coset(ax,ay,az),coset(0,0,lb-1),lz1)
+                    IF (ay == 0) THEN
+                      IF (ly1 > 0) s(coset(ax,ay,az),coset(0,1,bz),l) =&
+                                 f2y*s(coset(ax,ay,az),coset(0,0,bz),ly1)
+                      DO by=2,lb
+                        s(coset(ax,ay,az),coset(0,by,bz),l) =&
+                          f3*s(coset(ax,ay,az),coset(0,by-2,bz),l)
+                        IF (ly1 > 0) s(coset(ax,ay,az),coset(0,by,bz),l) =&
+                                 f2y*s(coset(ax,ay,az),coset(0,by-1,bz),ly1)
+                      END DO
+                      s(coset(ax,ay,az),coset(0,1,bz),l) =&
+                        fy*s(coset(ax,ay-1,az),coset(0,0,bz),l)
+                    END IF
+                    IF (ax == 0) THEN
+                      DO by=0,lb-1
+                        IF (lx1 > 0) s(coset(ax,ay,az),coset(1,by,bz),l) =&
+                                 f2x*s(coset(ax,ay,az),coset(0,by,bz),lx1)
+                      END DO
+                      DO bx=2,lb
+                        DO by=0,lb-bx
+                          s(coset(ax,ay,az),coset(bx,by,bz),l) =&
+                            f3*s(coset(ax,ay,az),coset(bx-2,by,bz),l)
+                          IF (lx1 > 0) s(coset(ax,ay,az),coset(bx,by,bz),l) =&
+                                 f2x*s(coset(ax,ay,az),coset(bx-1,by,bz),lx1)
+                        END DO
+                      END DO
+                      DO by=0,lb-1
+                        IF (lx1 > 0) s(coset(ax,ay,az),coset(1,by,bz),l) =&
+                                 f2x*s(coset(ax,ay,az),coset(0,by,bz),lx1)
+                      END DO
+                      DO bx=2,lb
+                        DO by=0,lb-bx
+                          s(coset(ax,ay,az),coset(bx,by,bz),l) =&
+                            f3*s(coset(ax,ay,az),coset(bx-2,by,bz),l)
+                          IF (lx1 > 0) s(coset(ax,ay,az),coset(bx,by,bz),l) =&
+                                 f2x*s(coset(ax,ay,az),coset(bx-1,by,bz),lx1)
+                        END DO
+                      END DO
+                    END IF
+                  END DO
+                END DO
+              END DO
+            END IF
+            IF (lb_max > 0) THEN
+              DO lb=2,lb_max
+                IF (lz1 > 0) s(1,coset(0,0,lb),l) = s(1,coset(0,0,lb),l) +&
+                             f2z*s(1,coset(0,0,lb-1),lz1)
+                IF (ly1 > 0) s(1,coset(0,1,bz),l) = s(1,coset(0,1,bz),l) +&
+                             f2y*s(1,coset(0,0,bz),ly1)
+              DO by=2,lb
+                s(1,coset(0,by,bz),l) = rbp(2)*s(1,coset(0,by-1,bz),l) +&
+                                       f2*REAL(by-1,dp)*s(1,coset(0,by-2,bz),l)
+                IF (lx1 > 0) s(1,coset(1,by,bz),l) = s(1,coset(1,by,bz),l) +&
+                             f2x*s(1,coset(0,by,bz),lx1)
+              END DO
+              DO bx=2,lb
+                DO by=0,lb-bx
+                  IF (lx1 > 0) s(1,coset(bx,by,bz),l) = s(1,coset(bx,by,bz),l) +&
+                               f2x*s(1,coset(bx-1,by,bz),lx1)
+                END DO
+              END DO
+            END DO
+          END IF
+        END IF
+        END DO
+        DO k=2,ncoset(lc_max)
+          DO j=1,ncoset(lb_max)
+          END DO
+        END DO
+      END DO
+    END DO
+  END SUBROUTINE moment
+  SUBROUTINE diff_momop(la_max,npgfa,zeta,rpgfa,la_min,&
+                    order,rac,rbc,difmab,mab_ext)
+    REAL(KIND=dp), DIMENSION(:, :, :), &
+      OPTIONAL, POINTER                      :: mab_ext
+    REAL(KIND=dp), ALLOCATABLE, &
+      DIMENSION(:, :, :)                     :: difmab_tmp
+    DO imom = 1,ncoset(order)-1
+      CALL adbdr(la_max,npgfa,rpgfa,la_min,&
+                 difmab_tmp(:,:,2), difmab_tmp(:,:,3))
+    END DO
+  END SUBROUTINE diff_momop
+END MODULE ai_moments