Hi!
IEEE min/max are not commutative and in the pattern
(define_insn "ieee_<ieee_maxmin><mode>3<mask_name><round_saeonly_name>"
[(set (match_operand:VFH 0 "register_operand" "=x,v")
(unspec:VFH
[(match_operand:VFH 1 "register_operand" "0,v")
(match_operand:VFH 2 "<round_saeonly_nimm_predicate>"
"xBm,<round_saeonly_constraint>")]
IEEE_MAXMIN))]
the first operand is a register and only the second one is register/memory.
Now, the *minmax<mode>3_3 define_insn_and_split does
rtx tmp = force_reg (<MODE>mode, operands[3]);
rtvec v = gen_rtvec (2, tmp, operands[2]);
operands[5] = gen_rtx_UNSPEC (<MODE>mode, v, u);
where operands[3] is the const0_operand, so operands[2] can there be
a memory, but in the *minmax<mode>3_4 case
rtx tmp = force_reg (<MODE>mode, operands[3]);
rtvec v = gen_rtvec (2, operands[2], tmp);
operands[5] = gen_rtx_UNSPEC (<MODE>mode, v, u);
operands[2] goes into the operand which must be a REG, so it
is incorrect to split it into something that won't work.
Now, I've tried both disabling the define_insn_and_split and
the following patch, the former to the latter results in
movaps a, %xmm0
pxor %xmm1, %xmm1
- cmpltps %xmm0, %xmm1
- andps %xmm1, %xmm0
+ maxps %xmm1, %xmm0
movaps %xmm0, a
ret
on the testcase, so I think it is better to match it and force_reg
(it is a pre-reload splitter) than change "nonimmediate_operand"
to "register_operand" because it won't match in that case.
Bootstrapped/regtested on x86_64-linux and i686-linux, ok for trunk and
16.2?
2026-05-15 Jakub Jelinek <[email protected]>
PR target/125308
* config/i386/sse.md (*minmax<mode>3_4): Force also
operands[2] into a REG.
* gcc.target/i386/pr125308.c: New test.
--- gcc/config/i386/sse.md.jj 2026-04-30 10:18:13.816688874 +0200
+++ gcc/config/i386/sse.md 2026-05-14 21:16:32.951097873 +0200
@@ -3468,7 +3468,7 @@ (define_insn_and_split "*minmax<mode>3_4
u = UNSPEC_IEEE_MAX;
rtx tmp = force_reg (<MODE>mode, operands[3]);
- rtvec v = gen_rtvec (2, operands[2], tmp);
+ rtvec v = gen_rtvec (2, force_reg (<MODE>mode, operands[2]), tmp);
operands[5] = gen_rtx_UNSPEC (<MODE>mode, v, u);
})
--- gcc/testsuite/gcc.target/i386/pr125308.c.jj 2026-05-14 21:22:29.293954240
+0200
+++ gcc/testsuite/gcc.target/i386/pr125308.c 2026-05-14 21:22:03.967390890
+0200
@@ -0,0 +1,12 @@
+/* PR target/125308 */
+/* { dg-do compile } */
+/* { dg-options "-msse2 -O2 -ffloat-store" } */
+
+float a[4];
+
+void
+foo ()
+{
+ for (int i = 0; i < 4; i++)
+ a[i] = a[i] > 0 ? a[i] : 0;
+}
Jakub
