* i386: Fix unsigned int -> double conversion on i386 w/ -mfpmath=sse [PR100119]
@ 2021-04-22 14:35 Uros Bizjak
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From: Uros Bizjak @ 2021-04-22 14:35 UTC (permalink / raw)
To: gcc-patches
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2021-04-22 Uroš Bizjak <ubizjak@gmail.com>
gcc/
PR target/100119
* config/i386/i386-expand.c (ix86_expand_convert_uns_sidf_sse):
Remove the sign with FE_DOWNWARD, where x - x = -0.0.
gcc/testsuite/
PR target/100119
* gcc.target/i386/pr100119.c: New test.
Bootstrapped and regression tested on x86_64-linux-gnu {,-m32}.
Pushed to master.
Uros.
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diff --git a/gcc/config/i386/i386-expand.c b/gcc/config/i386/i386-expand.c
index 166c23ddb4d..516440eb5c1 100644
--- a/gcc/config/i386/i386-expand.c
+++ b/gcc/config/i386/i386-expand.c
@@ -1550,6 +1550,8 @@ ix86_expand_convert_uns_sixf_sse (rtx, rtx)
gcc_unreachable ();
}
+static rtx ix86_expand_sse_fabs (rtx op0, rtx *smask);
+
/* Convert an unsigned SImode value into a DFmode. Only currently used
for SSE, but applicable anywhere. */
@@ -1569,6 +1571,11 @@ ix86_expand_convert_uns_sidf_sse (rtx target, rtx input)
x = const_double_from_real_value (TWO31r, DFmode);
x = expand_simple_binop (DFmode, PLUS, fp, x, target, 0, OPTAB_DIRECT);
+
+ /* Remove the sign with FE_DOWNWARD, where x - x = -0.0. */
+ if (HONOR_SIGNED_ZEROS (DFmode) && flag_rounding_math)
+ x = ix86_expand_sse_fabs (x, NULL);
+
if (x != target)
emit_move_insn (target, x);
}
diff --git a/gcc/testsuite/gcc.target/i386/pr100119.c b/gcc/testsuite/gcc.target/i386/pr100119.c
new file mode 100644
index 00000000000..be9472eb939
--- /dev/null
+++ b/gcc/testsuite/gcc.target/i386/pr100119.c
@@ -0,0 +1,28 @@
+/* PR target/100119 */
+/* { dg-do run { target sse2_runtime } } */
+/* { dg-require-effective-target fenv } */
+/* { dg-options "-O2 -frounding-math -msse2 -mno-avx512f -mfpmath=sse" } */
+
+#include <fenv.h>
+
+double
+__attribute__((noinline))
+test (unsigned int x)
+{
+ return x;
+}
+
+int
+main ()
+{
+ double result;
+
+ fesetround (FE_DOWNWARD);
+
+ result = test (0);
+
+ if (__builtin_signbit (result) != 0)
+ __builtin_abort ();
+
+ return 0;
+}
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2021-04-22 14:35 i386: Fix unsigned int -> double conversion on i386 w/ -mfpmath=sse [PR100119] Uros Bizjak
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